* {
  margin: 0;
  padding: 0;
}

.y1 {
  height: 400px;
  width: 1200px;
  //background-color: red;
  margin: 50px auto;
  position: relative;
}

.images {
  width: 100%;
  height: 100%;
  //background-color: red;
  list-style: none;
  position: relative;
}

.images > li {
  width: 100%;
  height: 100%;
  background-color: cadetblue;
  position: absolute;
  left: 0;
  top: 0;
  display: none;
}

.images > li.t1 {
  display: block;
}

.left,
.right {
  width: 50px;
  height: 50px;
  //background-color: rgba(0, 0, 0, 0.5);
  color: #fff;
  text-align: center;
  line-height: 40px;
  position: absolute;
}

.left {
  border-radius: 0 20px 20px 0;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
}

.right {
  border-radius: 20px 0 0 20px;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
}

.pointer {
  width: fit-content;
  height: 12px;
  position: absolute;
  bottom: 15px;
  left: 50%;
  transform: translateX(-50%);
}

.pointer > .s1 {
  width: 12px;
  height: 12px;
  margin-right: 4px;
  border: 1px solid rgba(0, 0, 0, 0.05);
  background: rgba(255, 255, 255, 0.4);
  display: inline-block;
  border-radius: 50%;
}

.pointer > .s1.s2 {
  background-color: #ffffff;
  width: 9px;
  height: 9px;
  position: relative;
  top: 2px;
  left: 0;
  border: 3px solid rgba(0, 0, 0, 0.1);
}

.pointer > .s1.s3 {
  background-color: #ffffff;
  width: 9px;
  height: 9px;
  position: relative;
  top: 2px;
  left: 0;
  border: 3px solid rgba(0, 0, 0, 0.1);
}

.y1 ul {
  width: 1200px;
  height: fit-content;
  display: flex;
  position: absolute;
  top: 0;
  left: 0;
  animation: auto_run 15s linear infinite;

  li {
    width: 1200px;
    height: 400px;
    background-color: green;
    position: relative;

    img {
      width: 100%;
    }
  }
}

@keyframes auto_run {
  from {
    left: 0;
  }
  to {
    left: -29640px;
  }
}

